PHOENIX – The second half of Corbin Burnes’ 2018 season was spent in unfamiliar territory. A lifetime starting pitcher, the Brewers asked the right-hander to shift to the bullpen. His rise through the minors – it took him just 2.5 years to make it to Milwaukee – had the organization confident the transition would be smooth.

Burnes, a 24-year-old, finished the regular season with a 2.61 ERA in 38 innings last season. He established himself as one of the Brewers’ most reliable pitchers in one of baseball’s deepest bullpens in the postseason, where his numbers – 2.00 ERA with 11/1 strikeout-to-walk ratio in nine innings – helped lead the team within a game of the World Series.

In three spring-training outings, Burnes’ peripherals – an 8.44 ERA and 5/1 strikeout-to-walk ratio in 5.1 innings – are not very good. He is not worried, however, insisting that he is fine-tuning his game. On most mornings, Burnes can be seen inside the clubhouse discussing...